Capacitive sensor devices, otherwise known as touch sensor devices or proximity sensors are widely used in modern electronic devices. A capacitive sensor device is often used for touch based navigation, selection, or other input, in response to a finger, stylus, or other object being placed on or in proximity to a sensor of the capacitive sensor device. In such a capacity, capacitive sensor devices are often employed in computers (e.g. notebook/laptop computers), media players, multi-media devices, remote controls, personal digital assistants, smart devices, telephones, and the like.
Such capacitive sensor devices are often operated, at least in part, by a controller component such as an application specific integrated circuit (ASIC). The inputs and/or outputs of the controller component are typically used to drive the portions of the sensor devices and to measure capacitance(s) from the sensor devices. The measurements may include multiple inputs and/or outputs (e.g. receivers, transmitters and guards, etc.) and can include absolute and transcapacitive measurements.
With respect to transcapacitance, some capacitive implementations utilize transcapacitive sensing methods based on the capacitive coupling between sensor conductors. Transcapacitive sensing methods are sometimes also referred to as “mutual capacitance sensing methods.” A transcapacitive sensing method operates, for example, by detecting the electric field coupling one or more transmitting sensor conductors with one or more receiving sensor conductors in a sensor array. Proximate objects may cause changes in the electric field, and produce detectable changes in the transcapacitive coupling. Sensor conductors may transmit as well as receive, either simultaneously or in a time multiplexed manner. Sensor conductors that transmit are sometimes referred to as the “transmitting sensor electrodes,” “driving sensor electrodes,” “row drivers,” “transmitters,” or “drivers”—at least for the duration when they are transmitting. Other names may also be used, including contractions or combinations of the earlier names (e.g. “driving electrodes” and “driver electrodes.” Sensor conductors that receive are sometimes referred to as “receiving sensor electrodes,” “receiver electrodes,” “column receivers,” or “receivers”—at least for the duration when they are receiving. Similarly, other names may also be used, including contractions or combinations of the earlier names. In one implementation, a transmitting sensor electrode is modulated relative to a system ground to facilitate transmission. In another implementation, a receiving sensor electrode is not modulated relative to system ground to facilitate receipt.
With respect to a controller, the inputs/outputs of the controller may be configured at different times to measure different capacitances from the sensor device. For example, a grid of capacitive sensor elements of a capacitive sensor device's sensor array can be scanned to determine individual transcapacitances that can be integrated to capacitively image an input object or objects that are touching or proximate to the capacitive sensor array of the capacitive sensor device.